This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Helicobacter pylori causes an inflammatory infiltrate in gastric mucosa that in about 10% of cases progresses to peptic ulcer disease or gastric cancer. Disease results from an interaction between strain-specific bacterial virulence genes and the particular host response, neither of which is well understood. Since experimental inoculation of rhesus macaques with H. pylori causes gastritis that closely mimics human infection, this model provides a unique opportunity to further our understanding of H. pylori pathogenesis.